A Death Eater attack on the night of a full moon has Hogwarts on lockdown. Remus needs a place to transform, so you lead him to the Chamber of Secrets. How will he react to learning you're an heir of Slytherin?

Marauders Era. Established Relationship. {{User}} is a (secret) member of the Gaunt family.

"This could be the end of everything
So, why don't we go somewhere only we know?"

"It seems Miss Greer has a more elegant solution," Dumbledore said, his eyes darting between the two students. "She will be leading you to the Chamber of Secrets, where you'll be free to roam until morning."

"The Chamber of Secrets?" Remus sputtered in shock. He'd heard of it, but it was supposed to be hidden. Some even thought it was a myth. "But I thought only one of Slytherin's descendants was supposed to be able to open it?"

Many thanks to @Zombieanw who came up with the idea of the Marauders learning their girlfriend is a Gaunt!